ABSTRACT
The local In distribution in InGaN quantum wells was measured in samples which were grown by metalorganic vapor phase epitaxy and molecular beam epitaxy (MBE) varying systematically the metal-flux ratio and the growth rate. The size of the clusters does not depend on the growth conditions, but the amplitude of the composition fluctuations is influenced by the growth rate. In-concentration profiles along the growth direction show the effect of In desorption and In segregation during the growth. The effect of different growth rates was analysed with respect to the strength of the composition fluctuations. The InGaN was capped by 30 nm GaN after a growth interruption and increase ofT, up to 800°C. The In and Ga fluxes were varied under N-rich conditions by changing the MBE source temperatures. The In-concentration profile along the growth direction is characterized by a diffuse lower interface and a steep decrease of the In concentration towards the cap layer.
